Next up: Solar Photovoltaics.  The first thing that everyone needs to know about solar energy is that there are two basic types of solar panels: those that provide electricity (photovoltaic panels, or PV), and those that provide heat. They are two entirely different types of panels that work in entirely different ways, with different costs and benefits.  So when someone says: “I want solar,” I always clarify which kind first.  (“Passive” solar is another type, but that does not involve any equipment.)